A traditional digital camera includes an image sensor and processing circuitry for converting an optical image into digital data that can be stored or transmitted for viewing. Some image sensors perform analog optical sensing and digital logic processing on the same integrated circuit (IC). In some cases, the physical packaging of the IC is minimized to provide an image sensor that can placed in compact digital camera devices.
However, due to the physical and electrical integration the digital logic with the analog optical sensing, operations performed within the digital logic may generate interference or electrical noise that affects the analog operations. In some cases, the interference or noise produces a visible artifact or in a digital image that may be distracting or undesirable.
One traditional solution to reduce the effects of interference is to physically isolate the analog sensors from the digital logic processing. However, the increasingly compact physical packaging constraints may limit the amount of physical separation that can be accommodated. That is, to achieve sufficient physical isolation between the analog and digital portions of an image sensor, the size of the image sensor may be too large to fit into the limited space available in some types of digital cameras. This is particularly true for digital cameras that are integrated into a mobile telephone or other portable electronic device. Additionally, increasing demands in the processing capabilities of the on-board digital logic processing may further exacerbate interference problems between the circuitry.
Thus, there is a need for a system and technique for reducing the effect of digital logic interference on the quality of a digital image. The techniques disclosed herein can be used to produce a digital image having reduced or minimized visual artifacts without significantly increasing the size of the sensor or the drawbacks of some traditional noise reduction techniques.